[evlatests] Antennas 21 and 24

[Rick Perley]

    Barry arranged for antenna 21 to give me data to look at. 
(Apparently the focus table was empty, which apparently cuts of the data 
flow).  So now I see data at L and K bands, whereas before there were 
only blanks.  Barry says no focus tweaking has been done, so the results 
below are suspect. 

    At L-band, we get only noise on IFs A and C.  There is a weak signal 
present on B and D, enough to determine the delay to be -12 and -28 nsec 
for IFs B and D respectively.  (These numbers should be subtracted from 
the current values). 

    At X-band, I see fringes on all four IFs now, but with a remarkable 
delay:  -80 nsec (one full turn across 12 MHz!) for A and C, -40 for B 
and D.  The bandpasses don't look right for A and C, so perhaps some 
other problems remain.  The SNR, for all 4 IFs, after BP correction, are 
not good. 

    At K-band, 21 gives no sensible values. 

    Antenna 24:

    The B and D IFs have a large delay, for all frequencies:  -16 nsec.  
Could somebody do the appropriate action on the appropriate database?  
(16 needs to be subtracted from whatever values are there now). 

    Otherwise:

    Antenna 23 was out for service, and 16 is being rewired.  All other 
EVLA antennas worked pretty well, with some of the usual amplitude 
drops.  14B is still hopping about by 150 degrees and L and C bands 
(didn't check P), and 26 is still have the large phase clunks I've 
reported on earlier.